Hydrological characterisation of four Brazilian catchments using a simple rainfall-streamflow model

A rainfall–streamflow model featuring a unit hydrograph component is applied to four Brazilian catchments to characterise and quantify their quite different dynamic rainfall–streamflow behaviours. Using only catchment size (km2) and time series of daily rainfall, streamflow and air temperature, six dynamic response characteristics (DRCs) are estimated for each catchment. The DRCs include decay time constants for dominant quick- and slow-response components of streamflow, a time-averaged relative volumetric contribution to streamflow from slow flow (i.e. a slow flow index, SFI) and the size of a conceptual catchment wetness store. The six DRCs are compared for the four catchments in the context of their broad hydroclimatological features. Regionalisation of DRCs with respect to physical catchment descriptors (PCDs) is mentioned in terms of the prospect of continuous streamflow simulation at ungauged sites in Brazil from rainfall and PCDs.